/*
 *  Copyright 2005 The Apache Software Foundation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.mybatis.generator.api;

import static org.mybatis.generator.internal.util.ClassloaderUtility.getCustomClassloader;
import static org.mybatis.generator.internal.util.messages.Messages.getString;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.mybatis.generator.config.Configuration;
import org.mybatis.generator.config.Context;
import org.mybatis.generator.config.MergeConstants;
import org.mybatis.generator.exception.InvalidConfigurationException;
import org.mybatis.generator.exception.ShellException;
import org.mybatis.generator.internal.DefaultShellCallback;
import org.mybatis.generator.internal.NullProgressCallback;
import org.mybatis.generator.internal.ObjectFactory;
import org.mybatis.generator.internal.XmlFileMergerJaxp;

/**
 * This class is the main interface to MyBatis generator. A typical execution of the tool involves these steps:
 * 
 * <ol>
 * <li>Create a Configuration object. The Configuration can be the result of a parsing the XML configuration file, or it
 * can be created solely in Java.</li>
 * <li>Create a MyBatisGenerator object</li>
 * <li>Call one of the generate() methods</li>
 * </ol>
 * 
 * @see org.mybatis.generator.config.xml.ConfigurationParser
 * 
 * @author Jeff Butler
 */
public class MyBatisGenerator
{
    
    private Configuration configuration;
    
    private ShellCallback shellCallback;
    
    private List<GeneratedJavaFile> generatedJavaFiles;
    
    private List<GeneratedXmlFile> generatedXmlFiles;
    
    private List<String> warnings;
    
    private Set<String> projects;
    
    /**
     * Constructs a MyBatisGenerator object.
     * 
     * @param configuration The configuration for this invocation
     * @param shellCallback an instance of a ShellCallback interface. You may specify <code>null</code> in which case
     *            the DefaultShellCallback will be used.
     * @param warnings Any warnings generated during execution will be added to this list. Warnings do not affect the
     *            running of the tool, but they may affect the results. A typical warning is an unsupported data type.
     *            In that case, the column will be ignored and generation will continue. You may specify
     *            <code>null</code> if you do not want warnings returned.
     * @throws InvalidConfigurationException if the specified configuration is invalid
     */
    public MyBatisGenerator(Configuration configuration, ShellCallback shellCallback, List<String> warnings)
        throws InvalidConfigurationException
    {
        super();
        if (configuration == null)
        {
            throw new IllegalArgumentException(getString("RuntimeError.2")); //$NON-NLS-1$
        }
        else
        {
            this.configuration = configuration;
        }
        
        if (shellCallback == null)
        {
            this.shellCallback = new DefaultShellCallback(false);
        }
        else
        {
            this.shellCallback = shellCallback;
        }
        
        if (warnings == null)
        {
            this.warnings = new ArrayList<String>();
        }
        else
        {
            this.warnings = warnings;
        }
        generatedJavaFiles = new ArrayList<GeneratedJavaFile>();
        generatedXmlFiles = new ArrayList<GeneratedXmlFile>();
        projects = new HashSet<String>();
        
        this.configuration.validate();
    }
    
    /**
     * This is the main method for generating code. This method is long running, but progress can be provided and the
     * method can be canceled through the ProgressCallback interface. This version of the method runs all configured
     * contexts.
     * 
     * @param callback an instance of the ProgressCallback interface, or <code>null</code> if you do not require
     *            progress information
     * @throws SQLException
     * @throws IOException
     * @throws InterruptedException if the method is canceled through the ProgressCallback
     */
    public void generate(ProgressCallback callback)
        throws SQLException, IOException, InterruptedException
    {
        generate(callback, null, null);
    }
    
    /**
     * This is the main method for generating code. This method is long running, but progress can be provided and the
     * method can be canceled through the ProgressCallback interface.
     * 
     * @param callback an instance of the ProgressCallback interface, or <code>null</code> if you do not require
     *            progress information
     * @param contextIds a set of Strings containing context ids to run. Only the contexts with an id specified in this
     *            list will be run. If the list is null or empty, than all contexts are run.
     * @throws InvalidConfigurationException
     * @throws SQLException
     * @throws IOException
     * @throws InterruptedException if the method is canceled through the ProgressCallback
     */
    public void generate(ProgressCallback callback, Set<String> contextIds)
        throws SQLException, IOException, InterruptedException
    {
        generate(callback, contextIds, null);
    }
    
    /**
     * This is the main method for generating code. This method is long running, but progress can be provided and the
     * method can be cancelled through the ProgressCallback interface.
     * 
     * @param callback an instance of the ProgressCallback interface, or <code>null</code> if you do not require
     *            progress information
     * @param contextIds a set of Strings containing context ids to run. Only the contexts with an id specified in this
     *            list will be run. If the list is null or empty, than all contexts are run.
     * @param fullyQualifiedTableNames a set of table names to generate. The elements of the set must be Strings that
     *            exactly match what's specified in the configuration. For example, if table name = "foo" and schema =
     *            "bar", then the fully qualified table name is "foo.bar". If the Set is null or empty, then all tables
     *            in the configuration will be used for code generation.
     * @throws InvalidConfigurationException
     * @throws SQLException
     * @throws IOException
     * @throws InterruptedException if the method is canceled through the ProgressCallback
     */
    public void generate(ProgressCallback callback, Set<String> contextIds, Set<String> fullyQualifiedTableNames)
        throws SQLException, IOException, InterruptedException
    {
        
        if (callback == null)
        {
            callback = new NullProgressCallback();
        }
        
        generatedJavaFiles.clear();
        generatedXmlFiles.clear();
        
        // calculate the contexts to run
        List<Context> contextsToRun;
        if (contextIds == null || contextIds.size() == 0)
        {
            contextsToRun = configuration.getContexts();
        }
        else
        {
            contextsToRun = new ArrayList<Context>();
            for (Context context : configuration.getContexts())
            {
                if (contextIds.contains(context.getId()))
                {
                    contextsToRun.add(context);
                }
            }
        }
        
        // setup custom classloader if required
        if (configuration.getClassPathEntries().size() > 0)
        {
            ClassLoader classLoader = getCustomClassloader(configuration.getClassPathEntries());
            ObjectFactory.addExternalClassLoader(classLoader);
        }
        
        // now run the introspections...
        int totalSteps = 0;
        for (Context context : contextsToRun)
        {
            totalSteps += context.getIntrospectionSteps();
        }
        callback.introspectionStarted(totalSteps);
        
        for (Context context : contextsToRun)
        {
            context.introspectTables(callback, warnings, fullyQualifiedTableNames);
        }
        
        // now run the generates
        totalSteps = 0;
        for (Context context : contextsToRun)
        {
            totalSteps += context.getGenerationSteps();
        }
        callback.generationStarted(totalSteps);
        
        for (Context context : contextsToRun)
        {
            context.generateFiles(callback, generatedJavaFiles, generatedXmlFiles, warnings);
        }
        
        // now save the files
        callback.saveStarted(generatedXmlFiles.size() + generatedJavaFiles.size());
        
        for (GeneratedXmlFile gxf : generatedXmlFiles)
        {
            projects.add(gxf.getTargetProject());
            
            File targetFile;
            String source;
            try
            {
                File directory = shellCallback.getDirectory(gxf.getTargetProject(), gxf.getTargetPackage());
                targetFile = new File(directory, gxf.getFileName());
                if (targetFile.exists())
                {
                    if (gxf.isMergeable())
                    {
                        source = XmlFileMergerJaxp.getMergedSource(gxf, targetFile);
                    }
                    else if (shellCallback.isOverwriteEnabled())
                    {
                        source = gxf.getFormattedContent();
                        warnings.add(getString("Warning.11", //$NON-NLS-1$
                            targetFile.getAbsolutePath()));
                    }
                    else
                    {
                        source = gxf.getFormattedContent();
                        targetFile = getUniqueFileName(directory, gxf.getFileName());
                        warnings.add(getString("Warning.2", targetFile.getAbsolutePath())); //$NON-NLS-1$
                    }
                }
                else
                {
                    source = gxf.getFormattedContent();
                }
            }
            catch (ShellException e)
            {
                warnings.add(e.getMessage());
                continue;
            }
            
            callback.checkCancel();
            callback.startTask(getString("Progress.15", targetFile.getName())); //$NON-NLS-1$
            writeFile(targetFile, source, "UTF-8"); //$NON-NLS-1$
        }
        
        for (GeneratedJavaFile gjf : generatedJavaFiles)
        {
            projects.add(gjf.getTargetProject());
            
            File targetFile;
            String source;
            try
            {
                File directory = shellCallback.getDirectory(gjf.getTargetProject(), gjf.getTargetPackage());
                targetFile = new File(directory, gjf.getFileName());
                if (targetFile.exists())
                {
                    if (shellCallback.isMergeSupported())
                    {
                        source = shellCallback.mergeJavaFile(gjf.getFormattedContent(), targetFile.getAbsolutePath(), MergeConstants.OLD_ELEMENT_TAGS, gjf.getFileEncoding());
                    }
                    else if (shellCallback.isOverwriteEnabled())
                    {
                        source = gjf.getFormattedContent();
                        warnings.add(getString("Warning.11", //$NON-NLS-1$
                            targetFile.getAbsolutePath()));
                    }
                    else
                    {
                        source = gjf.getFormattedContent();
                        targetFile = getUniqueFileName(directory, gjf.getFileName());
                        warnings.add(getString("Warning.2", targetFile.getAbsolutePath())); //$NON-NLS-1$
                    }
                }
                else
                {
                    source = gjf.getFormattedContent();
                }
                
                callback.checkCancel();
                callback.startTask(getString("Progress.15", targetFile.getName())); //$NON-NLS-1$
                writeFile(targetFile, source, gjf.getFileEncoding());
            }
            catch (ShellException e)
            {
                warnings.add(e.getMessage());
            }
        }
        
        for (String project : projects)
        {
            shellCallback.refreshProject(project);
        }
        
        callback.done();
    }
    
    /**
     * Writes, or overwrites, the contents of the specified file
     * 
     * @param file
     * @param content
     */
    private void writeFile(File file, String content, String fileEncoding)
        throws IOException
    {
        FileOutputStream fos = new FileOutputStream(file, false);
        OutputStreamWriter osw;
        if (fileEncoding == null)
        {
            osw = new OutputStreamWriter(fos);
        }
        else
        {
            osw = new OutputStreamWriter(fos, fileEncoding);
        }
        
        BufferedWriter bw = new BufferedWriter(osw);
        bw.write(content);
        bw.close();
    }
    
    private File getUniqueFileName(File directory, String fileName)
    {
        File answer = null;
        
        // try up to 1000 times to generate a unique file name
        StringBuilder sb = new StringBuilder();
        for (int i = 1; i < 1000; i++)
        {
            sb.setLength(0);
            sb.append(fileName);
            sb.append('.');
            sb.append(i);
            
            File testFile = new File(directory, sb.toString());
            if (!testFile.exists())
            {
                answer = testFile;
                break;
            }
        }
        
        if (answer == null)
        {
            throw new RuntimeException(getString("RuntimeError.3", directory.getAbsolutePath())); //$NON-NLS-1$
        }
        
        return answer;
    }
}
